82角色互换 如何通过函数调用实现代表2个角色的变量互 相 三套方案 ■sWap 10 a swapo a swapo 哪个方案能成功?
8.2 角色互换 如何通过函数调用实现代表2个角色的变量互 相… 三套方案 ◼ swap1() ◼ swap2() ◼ swap3() 哪个方案能成功？
例83指针作为函数参数模拟角色互换 int main ( void) 调用哪个函数,可以交换man0 i int a= 1, b= 2, 中变量a和b的值? int*pa=&a, *pb=&b void swap(int x, int y), swap2( int *px, int*py ) swap3(int*px, int*py); swap1(a, b) printf (After calling swap1:a=%db=%dⅦn”,a,b) a=1;b=2 swap2(pa, pb); printf ("After calling swap2:a=%db=%dⅦn”,a,b); a=1; swap 3(pa, pb) printf After calling swap3: a=%d b=%dIn", a, b) return o
例8-3 指针作为函数参数模拟角色互换 int main (void) { int a = 1, b = 2; int *pa = &a, *pb = &b; void swap1(int x, int y), swap2( int *px, int *py ), swap3 (int *px, int *py); swap1 (a, b); printf (“After calling swap1: a=%d b=%d\n”, a, b); a = 1; b = 2; swap2(pa, pb); printf (“After calling swap2: a=%d b=%d\n”, a, b); a = 1; b = 2; swap3(pa, pb); printf (“After calling swap3: a=%d b=%d\n”, a, b); return 0; } 调用哪个函数，可以交换main () 中变量a和b的值?
例8-3sWap10 swap1(a, b) void swap1 (int x, int y) I int t; y= t;
例8-3 swap1() swap1 (a, b); void swap1 (int x, int y) { int t; t = x; x = y; y = t; }
例8-3sWap20 swap2(&a, &b); void swap2 (int *px, int *py) t int t t=*px px="py, py =t;
例8-3 swap2() swap2 (&a, &b); void swap2 (int *px, int *py) { int t; t = *px; *px = *py; *py = t; }
例8-3sWap30 swap&a, &b); void swap int *px, int *py) int"pt t= px px= py, After calling swap1: a=1, b=2 After calling swap2: a=2, b=1 py= pt, After calling swap: a=1, b=2
例8-3 swap3() swap3 (&a, &b); void swap3 (int *px, int *py) { int *pt; pt = px; px = py; py = pt; } After calling swap1: a=1, b=2 After calling swap2: a=2, b=1 After calling swap3: a=1, b=2